1. Field of the Invention
The present invention relates to cargo transportation. More specifically, the present invention relates to the movement of cargo between the various modes by which it is transported. More specifically yet, the present invention relates to an apparatus and method for moving cargo into and out of cargo containers at shipping terminals and in particular at terminals for ocean-going shipping; storage of cargo; and delivery of inbound cargo and receipt of outbound cargo.
2. Description of Prior Art
For the past fifty years, much of world-wide shipping of goods has taken place in the form of containerized cargo. The containerized cargo method involves the filling of a containerxe2x80x94usually of a standardized size and shapexe2x80x94with goods at the goods"" point of origin and then leaving the goods in that container until they reach their point of destination. In general there will be a number of intermediate way-stations to which the containers are taken. Key among these way stations are usually the shipping terminals at which the cargo-filled container begins or concludes the ocean or sea-going segment of its journey from origin to destination. For the sake of definitiveness in this discussion, these shipping terminals will be taken to be terminals for ocean-going cargo ships, that is, marine terminals.
The containers in question are either 20 or 40 feet in outside length, with an outside width of 96 inches and a usual outside height of 8.5 feet. In general, each of them will be filled, also called xe2x80x9cstuffedxe2x80x9d, with numerous items, on pallets or not. This xe2x80x9cstuffingxe2x80x9d is, as stated, carried out at the point of origin and is generally carried out by a combination of manual and machine operations, using fork-lifts and the like. Thus, the stuffing operation can be a tedious and often dangerous operation for the workers and equipment, one that always has a certain risk of damaging the container itself.
The containers generally have no rollers or other means to make them easily moved from one location to the next. They therefore often require rollable chassis on which to be moved, for example, from the point of delivery at a terminal to the point where they are going to be loaded onto the ship.
At the conclusion of the ocean voyage the process is reversed, and the cargo-filled container is lifted from ship to ship-side, ultimately to be moved to and placed on ground transportation. Finally, with perhaps another intermediate stop, the cargo-filled container arrives at its point of destination where the container is emptied (xe2x80x9cstrippedxe2x80x9d) of its goods, again through a combination of manual and mechanized effort.
The usual situation is that at the point of destination for the goods in a particular container there are no goods with which to load the container for its return trip. Consequently, most containers return empty to the marine terminal. This is an inefficient use of transportation equipment, be it land-, air-, or ocean-based. There is an additional built-in disadvantage where trucks are concerned, regardless of whether the containers being carried are filled or empty, and that is that the size of the containers, standardized decades ago at 35 or 40 feet, is smaller than the size allowed to be pulled on the highways today. Modern semi-trailers have outside widths of 102 inches and, commonly, lengths of 53 feet. Thus, semi-trailers are often underutilized, because they are pulling 35 or 40 foot containers when they could be pulling 53 foot containers. This means that the trucking industry significantly under-utilizes the highways by having trucks pull a lower shipping volume than allowed, yet overloads the highways by using more trucks than are necessary for the volume of goods being transported.
As can be seen, many disadvantagesxe2x80x94some of them not present originallyxe2x80x94are associated with traditional containerized shipping. In addition to the ones set out above and to be summarized below, another even more significant one needs to be added, one connected to the dynamics of shipping. To see this, picture the cargo vessel as having a certain number of slots for containers. To maximize the use of assets tied up in this vessel, it mustxe2x80x94to the extent practicablexe2x80x94be continually engaged in crossing the ocean with a full load of cargo, that is, fully loaded with filled cargo containers. Even ignoring container loss due to damage during the inland stuffing, stripping, and transportation, it is estimated that for this continual ocean-going activity to be maintained there must be a total of five containers to xe2x80x9csupportxe2x80x9d every container slot on the ship. It is clear, for example, that within the 24-72 hour turn-around time of a ship in port, there must be a stuffed container available at the terminal to take the place of the stuffed container just off-loaded from the arriving ship. Furthermore, since the land shipment round trip often takes more time than the ocean round trip, there must already be a third filled container in transit toward the terminal as the re-loaded ship departs. In addition and as noted above, the full container that arrives at its destination and is stripped will not in general have goods ready at that point for re-stuffing; it must therefore be carried empty to another source of goods. And so forth. Moreover, the volume of cargo trade is very often physically imbalanced and, as a result, containers must frequently be xe2x80x9crepositioned,xe2x80x9d that is, moved as empty containers from a location of lower volume to a trading location of higher volume. This xe2x80x9crepositioningxe2x80x9d is a significant factor in the high cost of the present method of transporting cargo.
The need for such a large number of xe2x80x9csupportxe2x80x9d containers for each container slot has a number of costs in addition to that associated with having capital tied up in the containers. These containers must be stored somewhere during their transit, stuffed or empty. This means that valuable real estate is taken up as an inherent feature of the present cargo transport method. Furthermore, to address the damage problem, the more containers there are, the more containers will be damaged each year to the point where they need to be replaced. This replacement-requiring damage occurs while the containers are being moved on and off rolling stock, while they are being move and stacked in storage areas, etc.
In short, the basic idea of 50 years ago, introduced to reduce perceived widespread loss in shipment no longer works economically in the modem world. A number of attempts have been made to xe2x80x9cpatchxe2x80x9d the problem. These include the following. A method and apparatus for loading automobiles into a cargo container is taught by Bates et al. (U.S. Pat. No. 4,919,582). An apparatus and methods for containerizing and de-containerizing a load is taught by Harp (U.S. Pat. No. 4,832,560; 1989). A similar apparatus is taught by Harp (U.S. Pat. No. 5,044,866; 1991). Harp (U.S. Pat. No. 5,129,778; 1992) teaches a method and assembly for xe2x80x9cone-stepxe2x80x9d loading and unloading using essentially the invention taught in Harp ""560 and Harp ""866. An adjustable load-carrying apparatus for fully utilizing transport enclosure space is taught by Halpin et al. (U.S. Pat. No. 5,454,672; 1995). Nevertheless, none of these prior art solutions really solves the problems set out above.
Therefore, what is needed is a way to reduce the costs, human and economic, inherent in the container-stuffing and -stripping of the present shipping process. What is further needed is a way to reduce the inefficiencies inherent in the mis-fit between container size and cargo-space of land-transportation means. What is yet further needed is a way to reduce the total number of containers needed to support each container slot of a working cargo ship, thereby reducing the total world container inventory, to increase asset utilization of marine terminals and inland transportation, and optimize the infrastructure.
Believing that what is needed is not a xe2x80x9cpatchxe2x80x9d but a complete shift in the worldwide approach to cargo shipping, the present inventor presents an invention built around a xe2x80x9ccontainer sledxe2x80x9d apparatus and method for using same. The heart of the invention is a sled that is loaded with cargo at the marine terminal, cargo that has been transported by inland means from its point of origin without having to have been stuffed into a container. Once the container sled is loaded, it is moved to the container and inserted into the container. The container is next placed on-board the ship. At the conclusion of the ocean voyage, the process is repeated in reverse, the sled is removed from the container and moved to a location in the terminal where the goods on the sled can be transferred to the ground transportation, leaving the sled behind in the terminal. Before being loaded onto a ship or ground transportation, the sled may be placed in a storage facility at the terminal to await further processing.
Thus, the present invention is made up of both a device (the container sled) and a method that together provide a potential for changing the current large-scale shipping procedures in such as way as to reduce significantly the human and economic cost of cargo-handling at the points of origin and destination of the goods and in such a way as to drastically reduce the numbers of containers needed and to eliminate intermediate pieces of equipment on which to convey containers from one location to another.
More particularly, the apparatus of the present invention is a platform having outer dimensions approximately equal to the inner dimensions of standard containers, a platform in which extendable support rollers, for example, casters, are embedded on the underside so as to make the platform easily rollable across any reasonably smooth surface, such as the floor of a container or of a warehouse floor. By its nature, the support roller arrangement is able to support the weight of the fully loaded platform. Although in the Preferred Embodiment of the present invention, the support rollers are casters deployed by means of a threaded rod that runs the length of the sled and a linkage system attached to this rod, any of a variety of known means for deploying and maintaining these casters will occur to one skilled in the art upon reading the description of the present invention as presented herein.
At equal spaced intervals around the perimeter of the platform may be a number of spring-loaded guide rollers that serve to help keep the container sled centered, or in general, laterally stable, while within a container. The platform may further include removable upright members that spaced around the platform perimeter to serve as aids in platform loading. Each of these upright members may also have a spring-loaded guide roller attached to its top end, to provide similar service to that of the guide rollers deployed around the perimeter of the platform.
Although, in one sense, the method of the present invention is an entire new shipping protocolxe2x80x94point-of-origin to point-of-destinationxe2x80x94built around the container sled, its heart lies specifically in the process by which cargo coming into a marine terminal is transferred from ground transport to a container sled and then to the ship, a process that will be mirrored at the marine terminal located at the other end of the cargo""s ocean voyage. In that sense, the method of the present invention includes the steps of taking cargo that has arrived by land transport, loading it onto a container sled, and moving the cargo-laden container sled to a temporary holding location from which it is subsequently moved into a container, i.e., the cargo-laden container sled is used to stuff the container, and situating the thus-stuffed container into its slot on the ship. At the other end of the ship run, it includes moving the sled with attendant cargo out of the container i.e., stripping the container, moving the container sled to a cargo holding point and then, from the holding point to surface transport that will move the cargo on toward its point of destination, after which the emptied container sled may be re-loaded with new cargo headed the other way, etc.
Throughout this Summary, reference to xe2x80x9ccontainersxe2x80x9d or xe2x80x9ccargo containersxe2x80x9d can also be understood as not being limited to those containers commonly used with ocean-going vessels, or to any specific industry. For example, xe2x80x9ccontainersxe2x80x9d also includes those insulated and/or refrigerated containers, commonly referred to as xe2x80x9cReeferxe2x80x9d containers, that are used for transporting perishable or frozen cargo. xe2x80x9cContainerxe2x80x9d can further mean truck trailers of any size, equipped for dry cargo or refrigerated cargo as used, for instance, in the xe2x80x9croll-on, roll-offxe2x80x9d (Ro-Ro) cargo transport industry.